Hydraulic valve timing controller

ABSTRACT

An inner rotor has a support portion which directly supports a most inner winding portion of a coil spring from a radially inner direction at a specified angle position in the circumferential direction. The coil spring is formed by winding a wire in such a manner that adjacent windings are contact with each other at a specified angle position. The adjacent windings are separated by a distance at a position which is apart from the specified angle position in a circumferential direction.

CROSS-REFERENCE TO RELATED APPLICATION

This application is based on Japanese Patent Application No. 2011-173211 filed on Aug. 8, 2011, the disclosure of which is incorporated herein by reference.

TECHNICAL FIELD

The present disclosure relates to a hydraulic valve timing controller which adjusts valve timing of a valve that is opened/closed by a camshaft driven by a torque transmitted from a crankshaft of an internal combustion engine.

BACKGROUND

A hydraulic valve timing controller has an outer rotor rotating with a crankshaft and an inner rotor accommodated in the outer rotor in such a manner as to rotate with a camshaft. A plurality of working chambers are defined in the outer rotor by the inner rotor.

Working fluid is introduced into or discharged from the working chamber, whereby the inner rotor rotates relative to the outer rotor in one rotational direction or the other rotational direction. According to a differential phase between these rotors, a valve timing of a valve is adjusted.

JP-2011-69316A (US-2011-0073056A1) shows a hydraulic valve timing controller provided with a coil spring of which outer end and inner end are respectively engaged with the outer rotor and the inner rotor. In a case where one rotational direction of the inner rotor is referred to as a deforming direction and the other rotational direction of the inner rotor is referred to as a biasing direction, the coil spring is twisted and deformed along with a relative rotation of the inner rotor in the deforming direction, whereby the inner rotor is biased relative to the outer rotor in the biasing direction. When the engine is off and no working fluid is introduced into the working chamber, the inner rotor is compulsorily rotated in the biasing direction relative to the outer rotor, so that a valve timing is appropriately adjusted for starting the engine.

Generally, as an engine speed is increased, an engine vibration is also increased. In the above valve timing controller, if an engine vibration frequency agrees with a primary natural frequency of the coil spring, the resonance will occur in the coil spring. As a result, it is likely that the coil spring may be mechanically damaged and its durability may be deteriorated.

Further, in the above valve timing controller, adjacent windings of wire of the coil spring are contact with each other at a single point between the outer end and the inner end. However, when the coil spring is twisted and deformed, the contacting adjacent windings are easily moved apart from each other. When the contacting adjacent windings are moved apart, the primary natural frequency of the coil spring is decreased. It is likely that the engine vibration frequency agrees with a primary natural frequency of the coil spring and the resonance will occur in the coil spring, which may cause mechanical damages.

SUMMARY

It is an object of the present disclosure to provide a hydraulic valve timing controller which has high durability.

A hydraulic valve timing controller adjusts a valve timing of a valve that is opened/closed by a camshaft driven by a torque transmitted from a crankshaft of an internal combustion engine. The controller includes: an outer rotor rotating synchronously with the crankshaft; an inner rotor rotating synchronously with the camshaft and defining an interior of the outer rotor into a plurality of working chambers into or from which a working fluid is introduced or discharged, whereby the inner rotor relatively rotates with respect to the outer rotor in one or the other circumferential direction; and a coil spring having a most outer winding portion and a most inner winding portion which are respectively engaged with the outer rotor and the inner rotor. The coil spring is spirally deformable in a deforming direction that is one of the circumferential directions in order to bias the inner rotor in a biasing direction that is the other of the circumferential direction.

The inner rotor has a support portion which directly supports the most inner winding portion from a radially inner direction at a specified angle position in the circumferential direction. The coil spring has one end engaged with an engaging point of the outer rotor, the other end engaged with a supporting point of the support portion, and multiple windings of a wire in spiral form. All adjacent windings of the wire are directly in contact with each other at the specified angle position; and all adjacent windings of the wire are separated by a distance at a position which is apart from the specified angle position in the circumferential direction.

Even if the engine vibration is increased according to an increase in engine speed, the primary natural frequency of the coil spring is larger than the engine vibration, whereby the resonance can be avoided with high reliability.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and other objects, features and advantages of the present disclosure will become more apparent from the following detailed description made with reference to the accompanying drawings. In the drawings:

FIG. 1 is a longitudinal sectional view showing a valve timing controller according to a first embodiment of the present invention, taken along a line I-I in FIG. 2.

FIG. 2 is a cross-sectional view taken along a line II-II in FIG. 1;

FIG. 3 is a cross-sectional view of a valve timing controller in an operational state different from FIG. 2;

FIG. 4 is a cross-sectional view a valve timing controller in an operational state different from FIGS. 2 and 3;

FIG. 5 is a front view of a valve timing controller shown in FIG. 1;

FIG. 6 is a front view of a valve timing controller in an operational state different from FIG. 5;

FIG. 7 is a front view of a valve timing controller in an operational state different from FIGS. 5 and 6;

FIG. 8 is a cross-sectional view of a valve timing controller taken along a line VIII-VIII in FIG. 1;

FIG. 9A is a front view showing a coil spring in a set condition;

FIG. 9B is a front view showing a coil spring in a free condition;

FIG. 10 is a schematic chart for explaining a characteristic of a biasing mechanism shown in FIG. 5;

FIG. 11 is a cross sectional view showing a valve timing controller according to a second embodiment;

FIG. 12 is a schematic chart for explaining a characteristic of a biasing mechanism shown in FIG. 11;

FIG. 13 is a cross sectional view showing a valve timing controller according to a modification of the first embodiment;

FIG. 14 is a cross sectional view showing a valve timing controller according to another modification of the first embodiment;

FIG. 15 is a cross sectional view showing a valve timing controller according to another modification of the second embodiment; and

FIG. 16 is a cross sectional view showing a valve timing controller according to the other modification of the first embodiment.

DETAILED DESCRIPTION

Multiple embodiments of the present invention will be described with reference to accompanying drawings. In each embodiment, the same parts and the components are indicated with the same reference numeral and the same description will not be reiterated.

First Embodiment

FIG. 1 shows a first embodiment of a hydraulic valve timing controller 1 which is applied to an internal combustion engine for a vehicle. The valve timing controller 1 is provided in a torque transmitting system where an engine torque is transmitted from a crankshaft (not shown) to a camshaft 2. The valve timing controller 1 adjusts a valve timing of an intake valve which is driven by a camshaft 2 with hydraulic oil as “hydraulic fluid”.

(Basic Configuration)

A basic configuration of the valve timing controller 1 will be described hereinafter. As shown in FIGS. 1 to 4, the valve timing controller 1 has an outer rotor 10 and an inner rotor 20. A rotational phase of the inner rotor 20 is varied relative to the outer rotor 20, whereby a valve timing is adjusted. A circumferential direction, a radial direction and an axial direction of the outer rotor 10 is the same as those of the inner rotor 20. A rotational phase of the inner rotor 20 relative to the outer rotor 10 is referred to as a differential phase of rotors.

The outer rotor 10 is a sprocket housing including a shoe housing 12, a sprocket plate 13 and a lock plate 14. The shoe housing 12 has a main body 120 and a plurality of shoes 122. Each of the shoes 122 is circumferentially arranged one after another at generally equal intervals on an inner surface of the main body 120 and radially inwardly projects therefrom. Also, an accommodation chamber 30 is defined between the adjacent shoes 122 in the circumferential direction. The sprocket plate 13 has a sprocket 130 which is linked with a crankshaft through a timing chain (not shown). During an operation of the internal combustion engine, a driving torque is transmitted from the crankshaft to the sprocket 130 such that the outer rotor 10 rotates in a clockwise direction in FIGS. 2 to 4 together with the crankshaft.

The inner rotor 20 is a vane rotor which is arranged between the plates 13 and 14 in the outer rotor 10. The inner rotor 20 has a shaft 200 and a plurality of vanes 202. The shaft 200 is shaped cylindrically and is comprised of a shaft body 200 a and a rotational bush 200 b. Both ends of the shaft body 200 a are slidably in contact with the plates 13 and 14, and its outer circumferential surface is slidably in contact with the end of each shoe 122. As shown in FIG. 1, the shaft body 200 a is coaxially connected to the camshaft 2 which penetrates a center hole 132 of the sprocket plate 13. The inner rotor 20 rotates in the clockwise direction in FIGS. 2 to 4 together with the camshaft 2 relative to the housing 11. The rotational bush (axial portion) 200 b penetrates a center hole 142 of the lock plate 14.

Each of the vanes 202 protrudes radially outwardly from the shaft 200 at regular intervals and is accommodated in the corresponding accommodation chamber 30. Axial both ends of the vane 202 are slidably in contact with the plates 13 and 14, and a radial top end of the vane 202 is slidably in contact with an inner surface of the shoe housing 12. Each of the vanes 202 divides the corresponding accommodating chamber 30 in circumferential direction into working chambers 32 and 33. The working oil is introduced into working chambers 32 and 33 or is discharged therefrom. When the working oil is introduced into the advance chamber 32 through an advance passage 34, a rotational torque is generated to rotate the inner rotor 20 in the advance direction “Da” relative to the outer rotor 10. Meanwhile, when the working oil is introduced into the retard chamber 33 through a retard passage 35, a rotational torque is generated to rotate the inner rotor 20 in the retard direction “Dr” relative to the outer rotor 10.

A specified vane 202 a has a lock member 22 and a lock spring 24. A column-shaped lock member 22 is biased by a lock spring 24 to be inserted into a lock hole 140. When the lock member 22 is inserted into the lock hole 140, the inner rotor 20 can not rotate relative to the outer rotor 10. Meanwhile, when the lock member 22 is disengaged from the lock hole 140 by receiving hydraulic pressure from at least one of the chambers 32 and 33, the inner rotor 20 can rotate relative to the outer rotor 10.

When the working oil is introduced into the advance chamber 32 and the working oil in the retard chamber 33 is discharged, the inner rotor rotates in the advance direction “Da” relative to the outer rotor 10. As a result, the differential phase between rotors 10 and 20 is varied in the advance direction, so that the valve timing is advanced. Meanwhile, when the working oil is introduced into the retard chamber 33 and the working oil in the advance chamber 32 is discharged, the inner rotor rotates in the retard direction “Dr” relative to the outer rotor 10. As a result, the differential phase between rotors 10 and 20 is varied in the retard direction, so that the valve timing is retarded.

FIG. 3 shows a situation where the differential phase is most retarded, and FIG. 4 shows a situation where the differential phase is most advanced. FIG. 2 shows a situation where the differential phase is fixed at an intermediate lock phase between the most retarded phase and the most advanced phase. This intermediate phase is realized when the engine is off, and this intermediate lock phase is a most appropriate phase for optimizing a startability of the engine.

(Biasing Mechanism)

Referring to FIGS. 1 and 5 to 7, a biasing mechanism 5 for biasing the inner rotor 20 toward the intermediate phase will be described, hereinafter.

The outer rotor 10 has an outer stopper 18 which protrudes from the lock plate 14 in an axial direction opposite to the shoe housing 12. This outer stopper 18 is a column pin which is eccentrically located with respect to a rotation center “Cr” of the rotors 10 and 20.

The rotational bush 200 b has a heptagonal profile as shown in FIGS. 5 to 8. One corner portion of the rotational bush 200 b radially outwardly protrudes more than the other corner portions. This protruding corner portion forms a support portion 204. According to the present embodiment, as shown in FIG. 8, an angle position of the support portion 204 is denoted by “SA”.

As shown in FIGS. 1 and 5 to 7, the inner rotor 20 includes a plate-shaped rotational arm 206 which radially outwardly extends from the rotational bush 200 b and an inner stopper 208 which axially extends from the rotational arm 206 toward the lock plate 14. The inner stopper 208 is a column-shaped pin which eccentrically locates with respect to the center “Cr” of the rotors 10 and 20. An eccentric amount of the inner stopper 208 is the same as that of the outer stopper 18. A rotational locus of the inner stopper 208 does not overlap with the outer stopper 18.

As shown in FIGS. 1 and 5 to 8, a coil spring 50 is disposed around the rotational bush 200 b. The coil spring 50 is formed by winding a metallic wire 52 spirally. The coil spring 50 is disposed in a clearance 500 between the lock plate 14 and the rotational arm 206 in such a manner that a winding center “Cs” of the coil spring 50 agrees with a rotation center “Cr” of the rotors 10 and 20.

In the coil spring 50, the wire 52 surrounding the rotational bush 200 b forms a most inner winding portion 520 having five bent portions in the circumferential direction. As shown in FIGS. 5 to 8, the most inner winding portion 520 is wound around the rotational bush 200 b in such a manner that the five bent portions 520 a respectively confront the corner portions of the bush 200 b. The corner portion 520 a which is most apart from the inner end 520 b in the advance direction “Da” is engaged with the support portion 204. The most inner winding portion 520 supported by the support portion 204 is always engaged with the inner rotor 20 at a supporting point “Pi”. Further, the most inner winding portion 520 which further extends from the support portion 204 in the advance direction “Da” is apart from the rotational bush 200 b radially outwardly, whereby a space 56 is formed between the portion 520 and the bush 200 b.

A most outer winding portion 522 of the coil spring 50 has an outer end portion 522 a which is bent in U-shape. Since the outer end portion 522 a is arranged on a rotational locus of the outer stopper 18 and the inner stopper 208, the outer end portion 522 a is engaged with at least one of the stoppers 18 and 208 according to the differential phase between rotors 10 and 20. In the present embodiment, as shown in FIG. 8, an engaging point “Po” between the outer end portion 522 a and the stopper 18, 208 is located in an angle range AA which is defined between the angle position “SA” and an angle position which is advanced by 90°. In the following description, when the most outer winding portion 522 and the most inner winding portion 520 are respectively engaged with the stopper 18 and/or 208 and the rotational bush 200 b as shown in FIGS. 5 to 9A, the condition of the coil spring 50 is referred to as a set condition. Moreover, when the most outer winding portion 522 and the most inner winding portion 520 are respectively disengaged from the stopper 18 and/or 208 and the rotational bush 200 b as shown in FIG. 9B, the condition of the coil spring 50 is referred to as a free condition.

Furthermore, the coil spring 50 is configured in such a manner as to satisfy a following formula:

Rno>T×N+Rsi   (1)

In this formula, “T” represents a thickness of the wire 52 in a radial direction, and “N” represents a number of turn of the wire 52 at the specified angle position “SA”. In FIG. 9A, “N” is “3”. Furthermore, “Rsi” represents a radial distance between the supporting point “Pi” and the center “Cs” of the coil spring 50 that is in the set condition. “Rno” represents a radial distance between a point “Pa” and the center “Cs” of the coil spring 50 that is in the free condition. The point “Pa” corresponds to the angle position “SA” of the coil spring 50 that is in the set condition. Specifically, as shown by a solid line in FIG. 8, when the coil spring 50 is released in the set condition, the point “Pa” is on the angle position “SA”.

When the coil spring 50 satisfies the above formula in the set condition, the windings of the wire 52 at the points “Pc1” and “Pc2” is always in contact with each other in the radial direction. In windings of the wire 52 between the points “Po” and “Pi” other than the specified angle position “SA”, the adjacent windings of the wire 52 is apart from each other to form a space 58 along circumferential directions “Da” and “Dr”.

When the differential phase between rotors 10 and 20 varies in the retard direction, the outer end portion 522 a of the coil spring 50 is brought into engagement with the outer stopper 18, as shown in FIG. 6. At this moment, since the inner stopper 208 is apart from the outer end portion 522 a in the retard direction “Dr”, a twist deformation is generated in the coil spring 50 according to the relative rotation. As a result, the inner rotor 20 receives a biasing force in the advance direction “Da” from the coil spring 50. That is, when the inner rotor 20 is retarded more than the intermediate lock phase, the coil spring 50 is twisted and deformed according to a rotation of the inner rotor 20 in the retard direction “Dr”. The coil spring 50 biases the inner rotor 20 in the advance direction “Da”.

Meanwhile, when the differential phase between rotors 10 and 20 varies in the advance direction, the outer end portion 522 a of the coil spring 50 is brought into engagement with the inner 208, as shown in FIG. 7. At this moment, since the outer stopper 208 is apart from the outer end portion 522 a in the retard direction “Dr”, no biasing force of the coil spring 50 is applied to the inner rotor 20. That is, when the inner rotor 20 is advanced more than the intermediate lock phase, it is prohibited that the coil spring 50 biases the inner rotor 20 without respect to the relative rotation between the inner rotor 20 and the outer rotor 10.

In the intermediate lock phase shown in FIG. 5, the most outer winding portion 522 is engaged with both the outer stopper 18 and the inner stopper 208 in order to correctly switch between the biasing and non-biasing of the inner rotor 20.

(Operation and Advantages)

An operation and advantages of the biasing mechanism 5 will be described hereinafter. According to the differential phase between the rotors 10 and 20, the most outer winding portion 522 is engaged with the outer stopper 18 or the inner stopper 208. With respect to the intermediate lock phase, the coil spring 50 biases the inner rotor 20 or the coil spring 50 is prohibited to bias the inner rotor 20. While performing a lost motion, the windings of the wire 52 which are adjacent in the radial direction is shown in FIG. 8.

That is, the windings of the wire 52 of between the engaging point “Po” and the supporting point “Pi” is in contact with each other at a plurality of points “Pc1” and “Pc2” which are adjacent in the radial direction on the specified angle position “SA”. Especially, the most inner winding portion 520 is directly supported by the support portion 204 at the specified angle position “SA”. The most inner winding portion 520 is wound around the rotational bush 200 b from the support portion 204 in the retard direction “Dr” and is apart from the support portion 204 in the advance direction “Da” from the support portion 204. Since the support portion 204 biases the wire 52 radially outwardly, the inner wire 52 is biased to the outer wire 52 radially at the points “Pc1” and “Pc2”. As a result, since the wire 52 is supported by the support portion 204 at the points “Pc1” and “Pc2”, it is restricted that the winding of the wire 52 moves apart radially from the adjacent winding of the wire 52 at the points “Pc1” and “Pc2”.

Since the coil spring 50 is formed to satisfy the above formula (1) in the set condition, the wire 52 is biased radially inwardly. When assembling the coil spring 50 in the set condition, the most outer winding portion 522 is engaged with the engaging point “Po”, so that the wire 52 is easily biased radially inwardly. At the specified angle position “SA”, this radial inward biasing force and the radial outward biasing force at the support portion 204 are surely applied to the wire 52 of between the engaging point “Po” and the supporting point “Pi”.

According to the above coil spring 50, as schematically shown in FIG. 10, the wire lengths “L1” and “L2” are ensured between the points “Pi”, “Pc1” and “Pc2”, which are shorter enough than the wire length between the point “Po” and the point “Pi”. Therefore, in a case that the primary mode vibration propagating between the points “Pi”, “Pc1” and “Pc2” is assumed as shown in FIG. 10, its primary natural frequency can be increased. Even if the engine vibration is increased according to an increase in engine speed, the primary natural frequency of the coil spring 50 is larger than the engine vibration, whereby the resonance can be avoided with high reliability.

The space 58 allows the coil spring 50 to twist and deform. Also, the space 56 allows the coil spring 50 to twist and deform. When the coils spring 50 is engaged with the outer stopper 18 or when the coil spring 50 is brought into engagement with the outer stopper 18 from the inner stopper 208, the twisted coil spring 50 surely biases the inner rotor 20. Thus, the resonance can be avoided with high reliability without deteriorating a biasing operation of the coil spring 50 to the inner rotor 20.

Second Embodiment

As shown in FIG. 11, a second embodiment is a modification of the first embodiment. A biasing mechanism 2005 has a first support portion 204 and a second support portion 2204 which support the wire 52 of the coil spring 50.

Specifically, the second support portion 2204 is a columnar pin which projects form the rotational arm 206 toward the lock plate 14. The second support portion 2204 is apart from the specified angle position “SA” in the circumferential direction on a specified radial line “SL” which passes through the first support portion 204 on the angle position “SA”. That is, the second support portion 2204 deviates from the angle position “SA” by about 90° in a circumferential direction. The second support portion 2204 is located at a space 58 which is defined between the most outer winding portion 522 and a next outer winding portion 2524.

The second support portion 2204 forms direct-support portions “Ps1” and “Ps2” which directly support the most outer winding portion 522 and the next outer winding portion 2524. Thereby, as schematically shown in FIG. 12, the wire lengths “L1” to “L4” which defines the primary natural frequency are ensured between the points “Ps1” and “Ps2” and the points “Pi”, “Pc1” and “Pc2”. Especially, antinode portions of the primary mode vibration illustrated by two-dots-dash line in FIG. 12 can be restricted by the second support portion 2204.

According to the above biasing mechanism 2005, even if the wire length between the point “Po” and the point “Pi” is set longer to increase the biasing force applied to the inner rotor 20, the primary natural frequency can be established greater than the supposed maximum engine vibration. Further, a space 58 is defined between the most inner winding portion 520 and the adjacent wire 2524 so that the coil spring 50 is allowed to twist and deform. Thus, the resonance can be avoided with high reliability without deteriorating a biasing operation of the coil spring 50 to the inner rotor 20.

Other embodiment

The present invention should not be limited to the disclosure embodiments, but may be implemented in other ways without departing from the sprit of the invention.

Specifically, in the first and the second embodiment, the number of the direct contact portions of the windings of the wire 52 at the position “SA” can be increased according to an increase in turn number of the coil spring 50. For example, in a modification shown in FIG. 13, a contact point “Pc3” is formed in addition to the contact points “Pc1” and “Pc2”.

FIG. 14 shows another modification in which the support portion 204 is formed by a columnar pin which projects from the rotational arm 206 of the inner rotor 20. Also, FIG. 15 shows another modification in which the second support portion 2204 is located in a space 58 between the most inner winding portion 520 and its adjacent wire 2524. In this case, the wire 52 can be directly supported by the second support portion 2204 at the point “Ps1” on the line “SL”.

FIG. 16 shows the other modification in which the coil spring 50 biases the inner rotor 20 without providing the inner stopper 208. In this case, the valve timing controller 1 may adjusts a valve timing of an exhaust valve, while the advance direction and the retard direction are reversed. 

1. A hydraulic valve timing controller which adjusts valve timing of a valve that is opened/closed by a camshaft driven by a torque transmitted from a crankshaft of an internal combustion engine, comprising: an outer rotor rotating synchronously with the crankshaft; an inner rotor rotating synchronously with the camshaft and defining an interior of the outer rotor into a plurality of working chambers into or from which a working fluid is introduced or discharged, whereby the inner rotor relatively rotates with respect to the outer rotor in one or the other circumferential direction thereof; and a coil spring having a most outer winding portion and a most inner winding portion which are respectively engaged with the outer rotor and the inner rotor, the coil spring being spirally deformable in a deforming direction that is one of the circumferential directions in order to bias the inner rotor in a biasing direction that is the other circumferential direction, wherein: the inner rotor has a support portion which directly supports the most inner winding portion from a radially inner direction at a specified angle position in the circumferential direction; the coil spring has one end engaged with an engaging point of the outer rotor, the other end engaged with a supporting point of the support portion, and multiple windings of a wire in spiral form; all adjacent windings of the wire are directly in contact with each other at the specified angle position; and all adjacent windings of the wire are separated by a distance at a position which is apart from the specified angle position in the circumferential direction.
 2. A hydraulic valve timing controller according to claim 1, wherein the inner rotor has an axial portion which protrudes axially outwardly from an interior of the outer rotor; the most inner winding portion is wound around the axial portion; and the support portion is formed by a part of the axial portion which protrudes axially outwardly at the specified angle position.
 3. A hydraulic valve timing controller according to claim 2, wherein the most inner winding portion is wound around the axial portion from the support portion in the deforming direction so as to be engaged with the inner rotor; and the most inner winding portion is apart from the support portion in the biasing direction.
 4. A hydraulic valve timing controller according to claim 1, wherein the inner rotor has a first support portion at the specified angle position and a second support portion which is located between adjacent windings of the wire at a position apart from the specified angle position in the circumferential direction in such a manner as to support the coil spring directly.
 5. A hydraulic valve timing controller according to claim 4, wherein the second support portion is located on a specified radial line which radially passes through the first support portion.
 6. A hydraulic valve timing controller according to claim 5, wherein the second support portion is located at one of clearances between adjacent windings on the specified radial line except at least one clearance on the specified radial line.
 7. A hydraulic valve timing controller according to claim 1, wherein the coil spring is configured in such a manner as to satisfy a following formula: Rno>T×N+Rsi wherein “T” represents a thickness of the wire in the radial direction, “N” represents a number of windings of the wire at the specified angle position, “Rsi” represents a radial distance between the supporting point of the support portion and a center of the coil spring that is in a set condition where the most outer winding portion and the most inner winding portion are respectively engaged with the outer rotor and the inner rotor, and “Rno” represents a radial distance between a point corresponding to the specified angle position and the center of the coil spring that is in the free condition where the most outer winding portion and the most inner winding portion are respectively disengaged from the outer rotor and the inner rotor.
 8. A hydraulic valve timing controller according to claim 7, wherein when the coil spring is in the set condition, the engaging point of the outer rotor is located in an angle range which is defined between the specified angle position and an angle position which is advanced from the specified angle position by 90°.
 9. A hydraulic valve timing controller according to claim 1, wherein it is prohibited that the coil spring biases the inner rotor when a condition where the most winding portion is engaged with the outer rotor is changed to another condition where the most winding portion is engaged with the inner rotor; all adjacent windings of the wire are directly in contact with each other at the specified angle position; and all adjacent windings of the wire are separated by a distance at a position which is apart from the specified angle position in the circumferential direction. 